Fitbit Flex 2 vs Charge 2: Activity tracker matchup
When it comes to activity trackers, Fitbit is the name most people will recognize. Its wearables are simple to use, reliable, look smart, provide great vitals statistics and have one of the best apps behind them. Right now, you can choose between eleven Fitbit devices for tracking steps and calories.
The San Francisco outfit understands the importance of keeping its fitness tracker line fresh. First quarter 2017 earnings figures show that its most three recent activity trackers, Charge 2, Alta HR and Flex 2, accounted for a massive 84% of the company’s revenue.
Essential reading: Choosing the right Fitbit tracker
Released in September 2016 along with the Charge 2, Flex 2 is is the company’s slimmest tracker yet. It is also the only Fitbit device that is water resistant. Here’s how it stacks up against the company’s most popular fitness wearable.
Fitbit Flex 2 vs Charge 2: Design
Flex 2 is a more minimalistic device in comparison to the Charge 2. The original Flex had a smooth finish, while the Flex 2 has a textured finish like most other Fitbit wearables. Its core unit is also some 30% smaller than its predecessor model, measuring 31.7 x 8.9 x 6.8 mm.
Inside you will find a 3-axis accelerometer and vibration motor. A simple LED display uses 5 color-coded lights to show progress towards your daily goal, and keeps you connected with call and text notifications.
The wearable comes with a rubber strap in both large and small sizes, and uses a button clasp for securing itself around your wrist. It comes in a number of design options so you’ll easily be able to find one to your taste. Simply pop the tracker out and slot it into a different color wristband, or choose from a range of fancy metal bangles or bracelets. You can even take this further and opt for a design from a well known fashion name such as Tony Burch.
The Charge 2 retains the look and feel from its predecessor but comes with some improvements such as an OLED display that is four times larger. The single button on the left allows you to wake the tracker and page through the menu. You can also do this by turning your wrist towards you or tapping on the screen.
An important difference between the Charge 2 and Flex 2 is the screen. While the Flex 2 only has LED lights, the Charge 2 black and white OLED display lets you see your activity stats and the time. Just like the Flex 2, you can also personalize a Charge 2 with additional bands. Its takes about 10 seconds to make the change.
Another important difference is the PurePulse heart rate sensor which can be found on the underside of the Charge 2. It sticks out a bit but once its on your wrist it does not feel uncomfortable. This is in addition to the 3-axis accelerometer, vibration motor and altimetre which can be found in Fitbit’s flagship wearable.
Fitbit Flex 2 vs Charge 2: Battery life and water resistance
Apart from the slimmer design, waterproofing is the biggest change to the Flex 2. Finally a Fitbit wearable you can take swimming swimming with you!
The device is water resistant up to 50 meters, whether you’re in the shower, pool or ocean, and it automatically tracks your pool swims including laps, duration and calories burned in the smartphone app. Charge 2 is only splash proof so make sure you remove it before diving into the pool.
 | Fitbit Flex 2 |  |
Both devices can keep going for around 5 days, depending on use, settings, and other factors. Which is not bad and compares favorably to the Apple Watch. To refuel – plug the proprietary charging cable into a USB port, connect it to your tracker making sure everything is properly aligned.
Fitbit Flex 2 vs Charge 2: Features
In terms of features, Flex 2 is an entry level fitness tracker. It monitors your steps, distance, calories, active minutes and hourly activity. Other features are fairly standard and include automatic exercise tracking, reminders to move, and personalised weekly exercise goals.
At night, Flex 2 will monitor how long and how well you sleep, set a sleep goal and bedtime reminder to form good habits and wake you up gently with a silent alarm. Sleep mode kicks in from your movements so all you have to remember is to wear your tracker to bed. When you wake up, sync your tracker to see last night’s sleep stats on the dashboard.
Once you have a Fitbit wearable wrapped around your wrist, its strength lies in the fact that you can largely forget about it. Both the Flex 2 and Charge 2 benefit from SmartTrack, which automatically recognizes select exercises and logs them in the smartphone app. Activities are recorded when you’ve been active for at least 15 minutes, but that time can be manually adjusted according to your preference.
Charge 2 goes a bit further by tapping into your smartphone’s GPS for more precise data, and allowing you to start a workout manually from the device. The latter means, you can see your real-time target heart rate zone and optimize your sessions for fat burning, a fitness boost, or performance benefits.
Plus you get stats on your resting heart rate. Outside of any specific ailment, a lower resting heart rate correlates very closely to a state of greater general fitness and health.
Fitbit has recently introduced new sleep features for Charge 2 and some of its other devices, but not Flex 2. ‘Sleep Stages’ uses accelerometer and heart rate data to more accurately estimate how long you spend in Light, Deep, and REM sleep stages each night. The app also sifts through the stats and offers advice on ways to improve your kip time.
Where the Flex 2 has an edge over the Charge 2 is in its ability to track swimming. Four strokes can be monitored: freestyle, breaststroke, backstroke and butterfly. To track your pace and distance, you need to enter the pool length in meters or yards into the Fitbit app before starting your swim. The device then automatically tracks the duration of your swim and the number of pool lengths you complete.
For more detailed data, head over to the app. As mentioned, the app is one of the best ones around, and is beautifully designed, intuitive and provides a host of stats without overwhelming you. The same software is used by all Fitbit trackers.
Both trackers will display notifications. When you get calls and texts, Flex 2 vibrates and flashes lights to let you know. Tap twice on the tracker to see how close you are to your daily goal. The Charge 2 will also show you calendar notifications and you will be able to see snippets of all information (such as who is calling or texting you), on the tracker’s display.
A feature that you will find on the Charge 2 but not on Flex 2 is Cardio Fitness Level. This is a measurement based on VO2 Max, and it provides information on how well your body uses oxygen when you’re working out at your hardest. It is widely accepted as the gold standard for grading cardiovascular fitness – the higher your VO2 Max, the more fit you are.
The other feature that you will find on the Charge 2 are Guided Breathing sessions. This is a relaxing mindfulness experience that calms your body and mind through personalized deep-breathing sessions called “Relax”.
Fitbit Flex 2 vs Charge 2: The bottom line
While there are some similarities, the Flex 2 and Charge 2 are aimed at two quite distinct markets. Flex 2 is a minimalistic device for someone who is after basic fitness tracking wrapped in an attractive package. And this is reflected in its lower price.
While both cover the basics, the Charge 2 also benefits from a heart rate sensor, altimeter for counting floors, more detailed sleep statistics, connected-GPS, Multi-Sport, Cardio Fitness level and “Relax” sessions. In the case of Flex 2, waterproofing is its main selling point.
 | Fitbit Charge 2 | |
If you are after an entry level, no hassle, affordable device, and can live without a heart rate tracker, the Flex 2 is a great option. This is also the only Fitbit wearable for swimmers. If you are a bit more serious about your fitness, Charge 2 brings much more to the table. For the average person who is after a solid 24/7 activity tracker, its still one of the best options out there.
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